locking/atomics: COCCINELLE/treewide: Convert trivial ACCESS_ONCE() patterns to READ_ONCE()/WRITE_ONCE()

Please do not apply this to mainline directly, instead please re-run the
coccinelle script shown below and apply its output.

For several reasons, it is desirable to use {READ,WRITE}_ONCE() in
preference to ACCESS_ONCE(), and new code is expected to use one of the
former. So far, there's been no reason to change most existing uses of
ACCESS_ONCE(), as these aren't harmful, and changing them results in
churn.

However, for some features, the read/write distinction is critical to
correct operation. To distinguish these cases, separate read/write
accessors must be used. This patch migrates (most) remaining
ACCESS_ONCE() instances to {READ,WRITE}_ONCE(), using the following
coccinelle script:

----
// Convert trivial ACCESS_ONCE() uses to equivalent READ_ONCE() and
// WRITE_ONCE()

// $ make coccicheck COCCI=/home/mark/once.cocci SPFLAGS="--include-headers" MODE=patch

virtual patch

@ depends on patch @
expression E1, E2;
@@

- ACCESS_ONCE(E1) = E2
+ WRITE_ONCE(E1, E2)

@ depends on patch @
expression E;
@@

- ACCESS_ONCE(E)
+ READ_ONCE(E)
----

Signed-off-by: Mark Rutland <[email protected]>
Signed-off-by: Paul E. McKenney <[email protected]>
Cc: Linus Torvalds <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Ingo Molnar <[email protected]>
This commit is contained in:
Mark Rutland 2017-10-23 14:07:29 -07:00 • committed by Ingo Molnar
commit 6aa7de0591
180 changed files with 383 additions and 385 deletions

View file

@ -163,14 +163,14 @@ int __gxio_dma_queue_is_complete(__gxio_dma_queue_t *dma_queue,
int64_t completion_slot, int update)
{
if (update) {
if (ACCESS_ONCE(dma_queue->hw_complete_count) >
if (READ_ONCE(dma_queue->hw_complete_count) >
completion_slot)
return 1;
__gxio_dma_queue_update_credits(dma_queue);
}
return ACCESS_ONCE(dma_queue->hw_complete_count) > completion_slot;
return READ_ONCE(dma_queue->hw_complete_count) > completion_slot;
}
EXPORT_SYMBOL_GPL(__gxio_dma_queue_is_complete);

View file

@ -121,7 +121,7 @@ static inline int64_t __gxio_dma_queue_reserve(__gxio_dma_queue_t *dma_queue,
* if the result is LESS than "hw_complete_count".
*/
uint64_t complete;
complete = ACCESS_ONCE(dma_queue->hw_complete_count);
complete = READ_ONCE(dma_queue->hw_complete_count);
slot |= (complete & 0xffffffffff000000);
if (slot < complete)
slot += 0x1000000;

View file

@ -255,7 +255,7 @@ long compat_arch_ptrace(struct task_struct *child, compat_long_t request,
int do_syscall_trace_enter(struct pt_regs *regs)
{
u32 work = ACCESS_ONCE(current_thread_info()->flags);
u32 work = READ_ONCE(current_thread_info()->flags);
if ((work & _TIF_SYSCALL_TRACE) &&
tracehook_report_syscall_entry(regs)) {